With the development of mobile terminal technology, the function required by the user gets more, the screen size gets bigger, and the battery capacity required by terminals also gets more, so the charger power for charging the cell phone gets higher. In the charging process with large current, many terminal users have encountered safety problem that the connector of the output terminal of the charger is burnt melted after the occurrence of micro-short circuit when the cell phone is charging, particularly for the current general connector of the Micro Universal Serial Bus recommended by the globe, due to the limit of structure and size, when in use by the user, a large amount of conductive liquid and metal powder is formed by the entry of foreign matter, the plug and the socket being damaged by slantingly inserting and pulling, the plug being bent and broken due to excessive force, resulting in the micro-short circuit of data line or charger within the plug; the micro-short circuit cannot achieve the protection condition of charger short circuit, causing the charger to continuously output power which is changed to heat at the plug of data line, finally resulting in that the data line or the charger plug or the cell phone interface are heated to melt, smoke and be on fire, etc. The mobile terminals of current brands in the market all have the similar problem such that the user worries about the safety when using the cell phone, more seriously causing damage to the human body and property of the user. The specification for the safety problem of such electrical products in high-end markets such as in Japan and Europe is strict. Such problem is an incident of product safety, and even the national law prescribes that all the products will be recalled with severe punishment if the malfunction reaches a certain level. As the battery capacity of the terminal products gets larger, the ratio of the occurrence and the influence of such problem get severe, so the solution for such problem gets urgent.
As for the charger safety of terminal products on the market, the safety detection and protection are merely conducted on the battery and cell phone, for example, in 201010296579.4, the temperature identification circuit used for battery protection board is only a temperature identification circuit added on the battery protection board, and only solves the problem of abnormal heating of the battery charging. The temperature protection for the charger and the terminal interface has not been implemented, but such problem is generally occurred on the market. Some high-end customers also put forward the requirement on this safety protection. The current terminal battery capacity and charger power are smaller, so the occurrence of such problem will become more prominent with the widespread use of large battery capacity and large power charger.